This Phase I SBIR application is submitted in response to the call by DHHS for new tests for qualitative measurement of HCV RNA for diagnosis of chronic HCV infection in patients. The need is for HCV RNA assays that are as reliable but less expensive and resource-demanding than current molecular assays. The new test proposed for research and development consists of rapid sample isolation, innovative signal amplification, and detection with a new proprietary Alderon biosensor. The innovation in this research lies in the creation of a new, inexpensive, low-cost, assay for HCV RNA by development of integrated RNA isolation and advanced electrochemical (eSystem) detection, whose feasibility and performance characteristics will be investigated in research with three specific aims. In Aim 1, we will seek to demonstrate a simple mode of making the viral RNA in biofluid samples available for our downstream eSystem assays. In Aim 2, we will investigate innovative HCV RNA detection using a patented signal amplification method (PESA) and a new capillary flow design for advanced, low-cost biosensors that generate target-dependent electrical currents that are measured with an eSystem reader/monitor developed by us. The assays will employ direct detection of target-specific enzyme labels for high sensitivity, without the wash steps usually required for enzyme-enhanced assays. Our low-cost readers will deliver controlled electrical pulses and monitor currents generated by the target-specific enzyme labels. The milestone for Aim 2 will be to determine whether this new mode of HCV RNA detection has a sensitive electrical response with accurate detection down to 500 IU/mL. The objective is a biosensor system with performance equal to that of existing FDA-approved, branched-probe (bProbe) assays, yet practical for wide spread use at point of care. In these Aim 2 studies, we will use Armored HCV RNA standards and mock clinical specimens consisting of the hepatitis C virus spiked into serum and plasma samples. In Aim 3, we will validate the Alderon HCV RNA Qualitative eSystem Assay with clinical specimens. Accomplishing these aims will show the feasibility of developing new eSystem qualitative HCV RNA tests that are as clinically useful and reliable as commercially available, FDA-approved tests for confirmatory testing of chronic HCV infections but at much lower cost and suitable for use in resource-limited communities. We anticipate that this new approach to qualitative HCV RNA testing will find use both as a clinical diagnostic and as a valuable research tool for the study of HCV chronic infections. The proposed eSystem technology to be developed in this project will have a high impact, as it brings lower-cost HCV testing to many more infected individuals. Additional impacts of project success will result from use of the basic technology to develop new tests for other RNA viruses, such as HIV.